Apparatus for producing helical coils



April 15, 1i968 P. E. THURMAN 3,378,045

APPARATUS FOR PRODUCING HELICAL COILS Filed March 17, 1966 *razrl 2INVENTOR.

United States Patent O 3,378,045 APPARATUS FOR PRODUCING HELICAL COILSPaul E. Thurman, Detroit, Mich., assignor to Hans Sickinger Co., WestBloomfield Township, Mich., a corporation of Michigan Filed Mar. 17,1966, Ser. No. 535,155 7 Claims. (Cl. 14092.94)

This invention relates to the production of helical wire coils forbinding together the sheets of writing pads, pamphlets, books or thelike which are perforated along one edge of the sheets and covers.

It is an object of the invention to provide a novel and improved methodand apparatus for producing such coils, which will enable the user tomake various pitches of spirals with a single tool assembly. Thus itwill be much less expensive for the manufacturer of spiral bound booksand pamphlets to provide himself with equipment for making differenttypes and sizes of binders.

It is another object to provide an apparatus of this character which isof a relatively simple and inexpensive nature, and is compatible withexisting equipment for the manufacture of spiral binders.

The manner of accomplishing the foregoing objects and other objects andfeatures of this invetnion will become apparent from the followingdescription of embodiments of the invention when read with reference tothe accompanying drawings, in which:

FIGURE 1 is a cross-sectional view in elevation of a supporting head forthe tool, showing the tool in position and with the mandrel and wiretherein;

FIGURE 2 is an enlarged view in elevation of the tool and mandrel, themandrel being partly broken away from purposes of clarity, and

FIGURE 3 is a perspective view of the tool, the mandrel being removed.

Briey, the illustrated embodiment of the invention comprises a coilingtool of elongated shape having a mounting ange at one end. The mainportion of the tool is roughly of semicylindrical shape, having a datside with a recess extending therealong, and a convex side. The recessis flared, and adapted to receive a flared mandrel which is rotatablydriven during use. The tool is also provided with a series of slotsextending in from the at side thereof and deep enough to go beyond thebottom of the recess. These slots are parallel to each other anddisposed at an angle equal to the average pitch of the coils to beproduced. The width of the slots is considerably greater than the wirethickness.

In use, the wire will be threaded through the slots and around themandrel, and the mandrel will then be rotated. This will cause the wireto be driven through successive slots, the wire passing around themandrel on its open side. By varying the angle at which the wire entersthe first slot, a considerable variation in the pitch of the coil can beproduced.

It has -been found that the variations in pitch which can be producedwith this construction, in which the mandrel is exposed and the wireunguarded around a substantial portion thereof, will be very muchgreater than the pitch variations which could be obtained withconventional tools, such as that shown in Patent No. 3,101,750, datedAug. 27, 1963 and entitled Apparatus for Producing Helical Coils. Theexact reason for this unexpected difference is not at present known tome but is believed to have something to do with the extent to which thewire is worked or deformed in the initial phases of its passage aroundthe mandrel and through the slots of the tool.

lReferring more particularly to the drawings, the coiling tool isgenerally indicated at 11 and is adapted to ICC be mounted on one end ofa stationary housing 12 of cylindrical shape. A pair of ball bearings 13ad 14 are mounted within housing 12, and rotatably support a shaft 15which is driven by means not shown. A mandrel 16 has a tapered end 17mountable within a complementary recess 18 in shaft 15. :Mandrel 16 isremovable from shaft 15 so as to be replaced by a mandrel of differentsize, and is ared in a forward direction. The purpose of this are is toinsure proper release of the coiled wire from the mandrel in case ithits an obstruction, as described more fully in the aforementionedpatent.

Tool 11 comprises a mounting portion 19 and a coiling portion 21, asseen in FIGURE 2. The coiling portion is of generally semicylindricalshape, with the mounting portion flaring outwardly therefrom at one end.Both portions have in common a at surface 22 which is interrupted by aforwardly ared concave recess 23 extending axially along the coilingportion 21, and a sharper rearwardly flared concave recess 24 inmounting portion 19, the latter recess terminating in a semicylindricalrecess 25. A flange 26 extends outwardly from the convex side ofmounting portion 19, and is adapted to be gripped by a fastening nut 27threadably mounted on the outer end of housing 12, as seen at FIG. l.

The upper and lower surfaces, 28 and 29 respectively, of coiling portion21 are ilat. A series of -transverse slots 29 are formed in coilingportion 21 of the tool, these slots being equidistantly spaced andparallel to each other, and penetrating surface 22 to a depth greaterthan the depth of recess 23. The inclination of slots 29 is equal to theaverage inclination of the coils to be formed by the tool. The width ofslots 31, and their depth beyond the bottom of recess 23, aresubstantially greater than the thickness of the wire 32 which is to beformed into the spiral coil, for example, about three times greater. Thebottoms of slots 31 are flat and parallel to surface 22. The distancebetween the slots is such that when wire 32 is coiled around mandrel 16,it will, with constant pitch, leave the bottom of each slot rand enterthe top of the next slot, as seen in FIGURE 2.

Although the plane of surface 22 is a diametral one, ythat is, passingthrough the axis .of recess 23, this need not be so to accomplish thepurposes of the invention. In other words, the portion of mandrel 16which is surrounded by tool 11 could be slightly more or less than Theflare angle of recess 23 is preferably the same as that of mandrel 16.The forward face 33 of tool 11 is at the same angle as slots 29. Theintersections 34 of slots 31 with surface 22 are beveled, as seen bestin FIG- URE 3.

In operation, :a guide indicated partially at 35 will be provided abovetool 11 so that the lead angle of wire 32 may be varied. This guide maybe shifted to the left or right as indicated by the double-ended arrow36 in FIG- URE l, thereby shifting the feed angle of the wire as shownby the solid and dot-dash lines in FIGURE 2. The wire will be firstmanually threaded through slots 31 and around mandrel 16 until it ispassed through all the slots.

Mandrel 16 will then be rotatably driven by shaft 15 in the direction ofarrow 37 of FIGURE 2, the wire being formed into a spiral by its contactwith the walls of slots 31. The spiral wire will be fed outwardly fromtool 11 and through the perforations 38 in a pack of sheets 39.

By adjusting the position of guide 35, it will be possible to obtainvarious pitches of spirals without changing tool 11 on mandrel 16. In atypical example, it has been found that a tool body 11 with a slot pitchof five slots per inch can be used to produce a spiral with anywherefrom four turns to six turns per inch. To produce live turns per inch,the wire would be fed at approximately the angle 3 shown in solid linesin FIGURE 2. To produce a coarser pitch, say four turns per inch, theangle of feed would be indicated by dot-dash position 32 of wire 32. Onthe other hand, .a production of a finer spiral pitch, for eX- arnple,six turns per inch, can be achieved by the feed angle indicated at 32".

While it will be apparent that the embodiment of the invention hereindisclosed is well calculated to fulfill the Objects of the invention, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. In a coiling tool construction for the production of spiral Wirebinders, an elongated body having a coiling portion of generallysemicylindrical shape, a mounting portion extending outwardly from oneend of said coiling portion, a concave recess on one side of said bodyextending the entire length thereof, a rotatable mandrel Within saidrecess, the side of the mandrel facing away from said recess beingexposed, and a series of parallel inclined slots in the coiling portionof said body extending inwardly from the side thereof having said recessand having a depth substantially greater than the depth of said recess,the width of said slots being substantially greater than the width of awire to be formed into a spiral coil by said tool.

2. The combination according to claim 1, the side of said coiling toolwith said recess having a surface in a diametral plane interrupted bythe recess and said slots.

3. The combination according to claim 1, the said concave recess beingoutwardly flared toward the forward end of said coiling portion, saidmandrel being provided with a corresponding flare.

4. The combination according to claim 2, said coiling portion havingparallel sides at right angles to said surface, the intersections ofsaid surface with said slots being beveled.

S. The combination according to claim 1, further provided with a guideadjacent said coiling tool and adjustable in the direction of thecoiling tool axis, said Wire passing through said guide before enteringthe first slot of said coiling tool, whereby the angle of feed of saidwire may be varied.

6. The combination according to claim 1, the distance between said slotsbeing such that a spiral wire of constant pitch may leave the bottom ofone slot and enter the top of the next slot adjacent said mandrel.

7. The combination according to claim 2, the bottoms of said slots beingat and parallel to said diametral plane.

References Cited UNITED STATES PATENTS 3,101,750 8/1963 Pfae 14C-92.3

CHARLES W. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner.

1. IN A COILING TOOL CONSTRUCTION FOR THE PRODUCTION OF SPIRAL WIREBINDERS, AN ELONGATED BODY HAVING A COILING PORTION OF GENERALLYSEMICYLINDRICAL SHAPE, A MOUNTING PORTION EXTENDING OUTWARDLY FROM ONEEND OF SAID COILING PORTION, A CONCAVE RECESS ON ONE SIDE OF SAID BODYEXTENDING THE ENTIRE LENGTH THEREOF, A ROTATABLE MANDREL WITHIN SAIDRECESS, THE SIDE OF THE MANDREL FACING AWAY FROM SAID RECESS BEINGEXPOSED, AND A SERIES OF PARALLEL INCLINED SLOTS IN THE COILING PORTIONOF SAID BODY EXTENDING INWARDLY FROM THE SIDE THEREOF HAVING SAID RECESSAND HAVING A DEPTH SUBSTANTIALLY GREATER THAN THE DEPTH OF SAID RECESS,THE WIDTH OF SAID SLOT BEING SUBSTANTIALLY GREATER THAN THE WIDTH OF AWIRE TO BE FORMED INTO A SPIRAL COIL BY SAID TOOL.